Telegraph system



- B. F. MERRITT.

TELEGRAPH SYSTEM.

APPLICATION FILED OCT. 10, 1917.

Patented July 12, 1921.

2 SHEETS-SHEET bmnju op kun fic B. F. MERRITT.

TELEGRAPH SYSTEM.- APPLICATION FILED OCT. 10', 1917.

1,384,396. Patented July 12, 1921.

Q 2 SHEETS-SHEET 2.

UNITED s mrss PATENT. OFFICE.

BENJAMIN E. mama, or EAST ORANGE, NEW JERSEY. rissrenonro WESTERN EE crnrc COMPANY, INCORPORATED, or NEW YOIB. K, nix, a1 CORPORATION orrmwvonx. I

(TELEGRAPH SYSTEM.

tain new and useful Improvements in Telegraph Systems, of-which the following 1s a full, clear, concise, and exact description.

This invention relates to telegraph -s ,s tems and more particularly-to systems or handling multiple distribution of messages from a common'or central station to a plurality of outlying stations. a

The principal'object of this invention is to provide a system for the handling of telegraphic service, wherein messages orlginating at a main Station are to be received simultaneously at a plurality of outlying stations connected by means of line conductors radiating irom the mam station, the

I arrangement of the equipment according to this invention being especially applicable to the distribution of newsltems or other press matter in connection with newspaper work or the publication of periodical literature.-

7 In general this system provides several different methods whereby signaling and communication operations may be earned on between the main station and the outlying stations all in a manner to render one method of signaling independent and non-interfering with other ones of the methods ofsignaling. This system also provldes that the main station may signal or communicate either selectively with a single one of the outlying stations, selectively with more than one of the outlying stations, or

collectively. to all of the outlying stations simultaneously.

In order that the advantages of the present system may be more readily understood the more important service features desirable in a system of this character will first be briefly considered. In connection with the regular transmission of press matter, say, from a tele raphic bureau to a number of newspaper o ces, it frequently transpires that important news items are received at the telegra h'bureau from which point such items shouill be immediately transmitted to the newspaper offices in precedence of less important press matter. In the handling of press traffic such important items are come monly referred to as flashes. Since a sys paper oflices.

Speiflcation of Letters Patent. Pat nt July 12, 1 2 Application filed October 10, 1917. seriai'no. 195,715.

tem of printing telegraph has 'proven to be suitable call signals at the outlying stations be operated by the central station attendant immediately preceding or coincident with the transmission of the more important news items, for which transmission of the less important press matter would of course be mterrupted. Such call signaling insures that the special items will receive the immediate attentionof attendants at the newsfurther service necessity for repeating any portion of a message which may not be properly'reproduced at perhaps one or more stations, all as well understood by those skilled in the art. In meeting this requirement the present system provides that from each outlymg station an individual signal correspondfeature ielates to the ing therewith may be operated at the main stati0n. Accordingly, on receiving such signal from one or more of the outlying stations the main station attendant may select only such stations as may have signaled and after communicating with them and repeating anyportion of a message or furnishing any other information which may have been' requested the attendant again establishes connection to resume sending simultaneously or collectively to all of the outlying stations. 7

In carrymg out the resent invention a preferred arrangement is based on the employment of equipment to permit simultaneous telegraph and. telept as services over each of several circuits which may radiate from a mainstation to outlying or substations. Telephone conversations and the necessary operation of call signals in connection therewlth being carrled on over a metallic loop or pair of conductors while the telegraph operations are worked simplex over such line pairs. 'The present invention also contemplates a modified arrangement to permit the telephone service to be dispensed with although retaining or providing a system of call signals similar to a portion of that employed with the-telephone service. It is, of course, well understood in the art that satisfactory telephone service requires each circuit to, be formed. of a suitably balancedline pair on which the insulation and the general condition of the construction.

does not include telephone service would therefore be of particular advantage in situations where the metallic loops may not be formed of line pairs and whereon the insulation and general condition of the lines are not maintained at. astandard sufficiently high for telephone service although the tele-' graphic and call signal working thereovermay be entirely satisfactory. Features com mon, however, to either arrangement relate to individual switching means to selectably connect to any of a plurality of circuits for either call signal or telegraphic operation, and master switching 'means for collectively grouping all circuits to permit simultaneous operation of either call signalsor' telegraphic transmission thereover. In connection with such switching, compensating devices are automatically controlled to maintain a constant or uniform current potential of the call signal and telegraphic currents on the line conductors irrespective of the number of lines on which signaling or telegraphing may be under way at any given time. a w

This invention is illustrated diagrammatically in the accompanying drawings in which only so much of a telegraphic, telephonic and call signal equipment is shown as willbe necessary to a clear understanding of the system. i

Referring to the drawing, Fi ure 1 .illustrates an arrangement in whic telephone and telegraph working and call signal operation may be carriedout. In Fig.2 is shown an alternate arrangement which pro- 1 vides for telegraphworklng and the opera- .tion ofcall signals.

The equipment shown in each figure of the drawing may be considered as present at a main telegraph station and referring first toFig. 1, a metallic circuit A formed of a pair of line conductors 10 and 11 will be understood as extending to a distant outlying station (not shown). These line conuctors are joined through adjustable rheostats 12 and 13 and windings 15 and-16 of a' repeating coil or transformer 14 Through translation effect in therepeating coil, current changes in the windings 15 and 16 when cumulative, one coil with the other, set up corres ending current changes in the windings 1 and 18 and viceversa: Therefore, assuming that the distant station is provided with an alternating current-magneto-generator suitable'for signaling and a telephone set for talking service, operation of the generator across the line conductors 10 and 11 will set up current action inthe repeatin coil 14 whereby induced currents in win ings 17 contacts 27 of a ringin control relay 26, a

condenser 31, the windlng of a drop signal 32 and the normal contacts 28 and 22 of the relay 26 and key 20, respectively. The drop 32 thereby operated closes its contacts 33 establishing a current source 34-to operate a signal 35. In response to such a call an at tendant moves a double pole two-way switch 37 to establish its contacts 38 and 39, thereby extending a bridged connection from the leads at the contacts 27 and 28 of the relay 26 to include the windings-17 and 18 of the repeating coil 14 with talking bus conductors 7 and 8, which extend to a telephone set (not shown) but labeled at the left-hand side in the drawing. A telephone conversationmay now be carried. on with the distant station on the line A. When, the main station-desires to call the station on the line A indikey 20 is operated, thereby separating its normal contacts 21 and 22 to disconnect the drop 24 v and the telephone buses and' to -vidually for telephone service, the ringing close its contacts 23 and 24, thereby connecting a ringing current generator 36 with the repeating coil windings 17 and. 18..

Translation of these currents through the repeating coil 14 cumulatively energizes the conductors 10 and 11 of line A, and operates a suitable call signal which may be assumed as present at the distant station. On this call being answered a telephone conversation may be carried on between the main station and theoutlying station as already described. By thro-wing the telephone switch 37 to the opplosite position its contacts 40 and 41 connect t 5 and 6 which extend to a second telephone set- (not shown) as labeled at the right-hand side in thedrawing.

A second line circuit B which may be considered as extending to a second outlying station is equi ped in a manner identica with the line A talking key 52 corresponding with the talking key 37 serves forv connecting the line circuit B to either .the

telephone bus conductors 5 and .6 of one telephone set, or to the bus conductors 7 and 8 extending to the other telephone set.

When' it is desired to send a call signal from the main station to both of the outlying stations simultaneously, a switch 53, preferably arranged to be operated as a knee or foot switch, is closed, thereby'connecting a source of current 54 by way of the bus conductor 4 and the contacts 44 of the switch 42 through the winding of the ringing relay 26. This relay thereby operated separates its contacts 27 and 28 to disconnect the drop signal 32 and the telephone conductors extending to the key37 and closing of the re-' lay contacts 29 and 30 establish connection from the generator 36 through the repeating e line A with telephone buses v coil 14 to operate a signal at the distant st'ation on the line A, as already described in connection with the ringing key 20.' Coincident with the energization of the relay 26, current from the bus conductor 4 branches through the contacts 49 of the switch 47 to the wlnding of'the ringing relay associated with the line B, thereby effecting operation of this relay to impress ringing current from the generator36 over the line B to operate a signal at the distant station thereon, all in a manner similar to the operations described for sitgnaling over the line A.

Re erring to the telegraphic portion of the system, for simplexing of the line A aconnection branching from a point 19 intermediate the windings 15 and 16 of the repeating coil 14 extends through thenormal contacts 43 of the switching key 42, the bus conductor 3, a surge reducing coil 55, the contacts 57 of a switch 56 and an impedance coil 59 to a telegraph transmitter 60,which for convenience has been shown as a manur tors 10 and 11 in a manner to render these ment comprising a rotary distributer 61 and a group of transmitter contacts 62, which may be considered as tape controlled, and receiving equipment (notshown) may also be considered as included with the distributer. It will be noted that the telegraph bus conductor 3 extends through the contacts 48 of the switch 47 to the neutral or difi'erentialpoint intermediate the two line side coils of the repeating coil associated with the line B, thereby establishing telegraphic service over the line B in simplex arrangement in a manner similar to that already described in connection with the line A. a

, I In case it is desired to send telegraphically from. the main station individually, say, to the station on line A, the switch 47 is operated to separate its contacts 48, thereby proportioned to be equal to the joint resistdisconnecting the telegraph bus 3 from the line B and connecting it over the contacts 50 through a compensatingresistance 51 to earth. The resistance 51 is calibrated or ance of the two line conductor paths which form the line B as routed through the telegraph equipment to earth at the distant station. It will, therefore, be clear that on sending from the telegraphic equipment at the main station the impulses will only traverse the line A in arallel with the compensating orartifici' resistance 51. The telegraphic impulses therefore .will have the same potential or current resistance drop at the bus conductor 3 and on the line A as present when the line B is grouped therelwith, instead of.-the resistance or artificial ine 51. c

It may be mentioned that operation of the switch 47 by separation of its contacts 49 disconnects the ringing relayof'the line B. Therefore, in case the foot switch 53 is operated during the-time the switch 47 stands operated, call signal current will only be transmitted outover the line A or any additional lines (not shown) which may be grppped with the latter line.

en it is desired to send or communicate telegraphically only with the station on line B, the switch 42. is operated, separating'its contacts 43 to disconnect the telegraph bus conductor 3' from the line A, and through the closing of the contacts 45 to connect this bus through a compensating resistance 46 to earth, the resistance 46 being. equal to the resistance of the telegraph circuit as simplexed over the line AJ.

The purpose of the adjustable resistances 12 and 13 in the line A and the correspondingresistances in the line B is to permit uniform balancing of the circuits irrespective of any difference in the size or gage of the line conductors, or any difi'erence in the length of the line circuits as compared one with another. To make this point clear letit be assumed that. the telegraphic devices are proportioned or adjusted to standards whereby wlth line batteries of predietermined potential {the most satisfactory work ing will be had when the actual resistance of theflline circuit conductors to each St8,-

tion is, say, 1000 ohms. Therefore, this resistance value for a simplexed circuit means that the loop resistance of the two line conductors would be 4000 ohms. Assuming that the loop resistance of the line A is equal to 1600 ohms, each one of the resistances 12- and 13 would require to be adjustedlto represent a resistance of 200 ohms, and assuming that the loop resistanceof the line B to be 1000 ohms the. calibrating resistance thereinwould require to be set to represent 500 ohms each. It will be clear that by this method of calibrating through adjusting the resistance in each line conductor of each circuit, a symmetrical branching or distribution of call signal currents, telephonic currents and telegraphic currents is efl'ecting, the equipmentfor sending out call siged in multiple operation from the central station between a plurality of lines extendingito several outlying stations.

eferring to Fig.2 of the drawing; the general layout of the arrangement s own therein has, for convenience of description,

- been made similar to that shown in Fig. 1

and,.where possible, like characters of reference have been employed in designating like parts. -In order to simplify the drawnal currents from the main station has not been shown, but it will be understood that, if

desired, equipment similar to that shown in .Fi 1 may be employed for such service.

n tracing an incoming call from the outlying station on the line A it will be understood that suitable ringin current would be applied to the line con uctors 10 and 11 at the distant station. Such currents translated throughthe repeating coil 14 complete circuit through the uppermost winding of source of current 67 to light a lamp signal 68. The relay 76 also operated establishes a source of current 77 to operate an auxiliary signal 78. In'theabsence of telephone instruments this call would be answered by .means of the telegraph, toaccomplish which the .key 70 is operated, whereby separation of its contacts 71 disconnects the locked relay 64, which in turn disconnects the lamp 68 and the auxiliary relay 76, whereby the signal 78 is disconnected. Closin of the contacts 73 of the key 70 connects t e source of current 75 through the winding of a relay 84 in seriestwith the winding of arelay 86,

, thence over the contacts 92 of a transfer key .90 to earth, thereby operating both of these rela s; Separation of the contacts 72 of-the key 70 disconnects the telegraph lead of theline A from a bus conductor 81 and connects it to a'bus conductor 82. Separation of the contacts 850i the relay 84 severs a tie connection whereby the bus conductor 81 is normally joined with the bus conductor 82, and

separation of the contacts 87- of the relay' 86 removes a shunt from around a resistance unit 89. These circuit chan es disconnect the telegraph'lead from the ,ine B and es- .tablish aconnection with the lineA which may betraced from a telegraph equipment resistance 121- to the differential .or

100 over an impedance 0011 101, a switch 102, the resistance unit 89, the contacts 93 ofthetrans'fer key 90, the bus conductor 82, the contacts 74' of the key 70,-anadjustable simplex point 19 of the line It will be understood that suitable receiving equipment is included with the transmitting set 100, whereby telegraphic communication may now be carried on individuseveral telegraph circuits in eflect the same as already described in connection with Fig. 1. This arrangement is permissible since the more important multiple sending from the main station is over the simplexed tele graph circuit, the call signal operations coming in individually from outlyling. stations as described. In setting up t. e switching operations to individually select and answer the station A, as just set forth, the compensating unit 89 iseffective serially withlthe telegraph lead to establish the same potential of the telegraph currents on the single line A as were present when this line was grouped with the line B. This may be made clear by assuming as an example that ten different lines similar to the lines A and B, and calibrated to a resistance of 1000 ohms each, are grouped for multiple transmission from the central station, at whichpoint the potential ofthe line current supply is 100 volts and the series resistance of the protective 'devices, impedance unit, etc., make a total of 25 ohms. Since the joint resistance of the ten 1000-ohm lines would equal 100" ohms, the potential. drop around the 25 ohms would be 20 volts, while the drop around the joint 100 ohms of the lines would be 80 Volts.

'v0 t line drop wouldbe to the single 1000- ohmline as 20 volts would be t0 250 ohms,

and since the telegraphic devices at the central station have a resistance of 25 ohms, as

already assumed, such twenty-five ohms would be subtracted from the total of 250 ohms which would give 225 ohms as the value for the resistance 89.

In the operation of this system it is de- 7 sirable at times to disconnect, perhaps, only one or a few stations from a multiple group and for this purpose a key switch and a compensating resistance is provided for each line.. A key 103 and'resistance 106 are ar ranged to render this service in connection-- I, with the line A, while a key 107 and the associated resistance efiect corresponding service for the line B. To disengage or disconnect the line A the key 103 1s operated, separating its contacts 104 to disconnect the line A from the bus conductor 81 to which it is normally connected through the contacts 72 of the answering key 70. Closing of the contacts 105 of thekey 103 connects the bus conductor 81 through the compensat- 86, the contacts 93 of the transfer key 90,

thence to the busconductor82, first branching through the contacts 85 of the relay 84,

to the bus conductor 81. From the latter bus these impulses branch, a portion of the current traversing the contacts 105 of the key 103 and the resistance 106 to earth, while the remainder traverse the contacts 108 of the key 107, the contacts 111 of the key 110,

thence over a calibrating resistance 115 to' the line B. It will be noted that the bus conductor is inefi'ective at this time since it stands 0 n-circ'uited at the contacts 74 of the key 0 and at the contacts 113 ofthe key 111'. For group or multiple service let it now be assumed that the key 103 is restored to its normal (position wherebthe re- 1 sistance unit 106 is sconnected an the bus conductor 81 is established overthe contacts 104 of the key 103 and the contacts 72 of the key 70 with the line A. In. transmitting from the instrument '100 the telegraphic im pulses reach the bus conductor 81, whence the currents branchequally over the lines A and B over the paths alread traced.

It will be understood that t e tele raph set 100 would preferably be arranged as a keyboard tele ra h set located on a telegra htable w ic also carries a tape control ed or automatic telegraph set 116 and that a second telegraph table contains the sets 118 and 120, which are in duplicate of the sets 100 and 116 respectively. The transfer key 90 isfor the p ose of transferring the telegra h service rom one table to the other. In describing this transfer feature of the system it will'be pointed out that the three relays 84, 86 and 119 are connected in series, but due to the key 90 only two of'the relays may be operated at one time. In the position shown the contacts 920i this key established a short circuit. around the winding of the relay .119, leaving the relays 84 and.86 responsive to. either of the answerin keys or 110. When the. key.

e normal position its contacts 91 90 is in' t establish a 'shortcircuit around the winding of the relay 86, thereby, rendering the relays 84 and 119 responslve to the answering I keys. The transfer key also conditions circults to permit local testing of the telegraph equipments on an idle table. When positioned as shown in the drawing the sets 100 and 116 on the left-hand table are connected for service over the circuits already traced, while local test circuits from the right-hand table may ,be traced from the tape controlled set 120 over the associated impedance coil, switch; and right-hand contacts of the relay 119, the contacts 94 of the key 90, thence through a resistance unit 97 which is calibrated to represent a resistance value equal to a group of multipled line circuits corresponding with the lines A and B. A second position of the key 90separates its contacts 93 and 94 and closes its contacts 95 and 96, the contacts 91.also being closed while the contacts 92 are open.-

Either one of the telegraph sets 118 or 120 now becomes efi'ective for service over the contacts 96 of the key 90, while either of the idle the single line answered as already described.

in connection with the-set 100. At each table the switches corresponding with the switch 102 for the set 100 serve to cut the associated set in' or out of circuit, it being; understood that only one set on each table may be in use at one time, either for line service or for-local testing, depending on the positionof the transfer key 90. The

purpose of the condensers, one legged to eart from each telegraph set, is for absorbing surges of current set up by the tele graph operations.

In reference to the capacity of the system, any number of branc ing lines may be added thereto by providin mdividual e ui ment for each'line, as ilustrated and (1E- scribed in connection with'the lines A and B.

For the arrangement shown in Fig. '1 of the' drawing such individual e m ment would interconnect from an adde line to the bus'conductors 1 to- 8 inclusive, while for the arrangement shown inFig. 2, the equipment for each additional line would interconnect to the bus conductors 'to 83 inclusive in a manner similar to the connections for the equi ments illustrated.

What is claimed 1s: 1. In a signaling system of simultaneous telegraphy and telephony, a plurality of line circuits, a central station and outlying stations connected by said line circuits,

means for telegraphing over said line' circuits, switching means for either selectively or collectively engaging said lines for telegraphing v thereover, and resistances con trolled by said switching means and substituted thereby for non-engaged lines.

2. The combination of a plurality of line circuits extending from one station, of apparatus at said stations for telegraphing over said lines, of means at said station for receiving call signals over said lines simultaneously with said telegraphing, switching means for either selectively or collectively engaging said lines, for use, artificial lines and means controlled by said switching means for substituting one of said artificial lines for each non-engaged one of said lines.

3. In a system of s1multaneous telegraphy and telephony, a main station, a plurality of outlying stations, line circuits extending from said main station to said outlying stations, means for either selectively or collectively engaging said lines for communication from said main station, and means for maintaining. uniform current consumption teleg'raphically on each en aged line irrespective of the number of lines under communication.

4. A system for permitting the simultaneous operation of both telegraphic and telephonic equipment comprising a central station, outlying stations, lines for connecting said outlying and said central stations, a resistance. means for simultaneously transmitnssasce ting telegraphic signals over said lines from.

nals. for said lines, and means for operating said call signals oversaid lines as selectivel or collectivel engaged simultaneously with said telegraphing.

6. The combination of a plurality of line circuits extending from one station, of apparatus at said station for telegraphing over said lines, equipment at said station for telephoning over said lines simultaneously with said telegraphing, equipment at said station for transmitting call signal operating currents over said lines simultaneously with said telegraphing, means for calibrating the resistance of each of said lines to a predetermined value, switching means for either selectively or collectively engaging said lines for use, a plurality of artificial lines, and means controlled by said switching means to substitute an artificial line for each line which may be non-engaged.

In witness whereof, I hereunto subscribe. my name this 5th day of October A. D. 1917.

BENJAMIN F. MERRIIT. 

